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TEST LO connector on the Model 75D and the other RG-58/U
cable is connected to the REMOTE TEST HI connector,,
b. Adjust the Model 75D front panel controls in accordance with
Table 4, except set the MULTIPLY C switch to 0.0001.
Co
Connect the free end of the REMOTE TEST LO cable to either
terminal on the CS-0.1 „
d.
Zero-balance the bridge as described in paragraph 3.5.
e.
Set the meter switch to ZERO CENTER.
If necessary, adjust the
C ZERO FINE control until the NULL INDICATOR pointer is
centered.
f.
Connect the free end of the REMOTE TEST HI cable to the remain¬
ing terminal on the CS-0.1 .
g„
Adjust the CAPACITANCE and CONDUCTANCE controls for a
center null indication on the meter.
Read the CAPACITANCE
dial and compare the reading with the CS-0.1 value.
h.
Refer to paragraph 1 .4,a, and check the pF reading derived in
Step g , above, for conformity with the capacitance accuracy
specification.
If the pF reading accuracy is as specified, proceed to
Step k , below.
If the accuracy of the pF reading is not
consistent with the specification, perform Steps i
through k ,
below.
i.
Set the CAPACITANCE control to the exact value stamped on
the CS-0.1 „
j.
Adjust C515 for a center null indication on the meter.
k.
Remove the CS-0.1 and coaxial cables.
Install the bridge
assembly cover plate (par. 4.13).
Install the Model 75D chassis
in its cabinet (par. 4.12).
4.11
BRIDGE ASSEMBLY CONDUCTANCE CALIBRATION CHECK.
a.
Calibration of the CONDUCTANCE control is beyond the capability of
the user since it involves special-purpose equipment and highly specialized
techniques.
The following procedures, however, will permit the user to
verify the calibration of the CONDUCTANCE control on all four ranges.
Follow the procedures as a semiannual check.
b.
Checking CONDUCTANCE R-Scale Calibration on the 1000 Multiplier Range.
(1)
Test equipment:
One 1 MQ deposited-carbon resistor, 1%, 1/4 watt or
1/2 watt.
(2)
Procedure:
a.
Adjust the Model 75D front panel controls in accordance with
Table 4.
b.
Remove the terminal shield from the front panel binding posts.
c.
Set the MULTIPLY C switch to 0.01.
d.
Zero-balance the bridge as described in paragraph 3.5.
75D
b-370
70
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